1. Technical Field
This invention relates generally to electronic devices having near field communication circuitry, and more particularly to a device having a near field communication circuit with a low-power mode, the circuit being able to detect when other near field communication circuits are within close proximity.
2. Background Art
Mobile devices today are becoming increasingly complex. By way of example, a mobile telephone was used—no too long ago—only for making telephone calls. Today, however, some mobile telephones are equipped with near-field communication technology, such as radio frequency identification (RFID) circuits. This near field communication technology can obtain information from other near field communication devices, deliver information to near field communication terminals, and even engage in financial transactions.
By way of example, some mobile device manufacturers have recently developed electronic, or “virtual,” cards in devices using near-field communication technology. For instance, Mastercard®, in conjunction with some mobile phone manufacturers, offers a virtual “PayPass”™ card that is stored within the memory of a mobile telephone. The virtual card is personalized (often by a trusted party on behalf of a financial institution) with information such as account number, name, and expiration date. This information is stored in memory as a virtual card. The mobile device then transmits the information wirelessly to payment terminals via near-field communication circuitry.
More modern devices are capable of operating as near-field readers as well. The near-field circuitry of these devices must be ON to start communication with a passive near-field device, such as a smart poster. (A smart poster is a poster that includes a near-field communication tag capable of being read by the wireless near-field transceiver. A smart poster for a movie may include a near-field communication tag having information about show times, movie merchandise, and the like. When a user passes an electronic device having a wireless near-field communication circuit within a predetermined distance of such a poster, the device may read the information and present corresponding information on the display.)
When reading such a smart poster, the user generally waves the electronic device having the near-field reader over the poster to download content or initiate an action such as launching a URL or dialing a number. However, the user must either press a button or otherwise use the user interface to enable the near-field reader. This process is cumbersome and inconvenient. The other alternative is to have the near-field reader continually ON, which impacts the battery life.
There is thus a need for an improved near-field communication circuit that does not operate continuously or require a user to actuate a button or interface.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.